The 370-store group, whose products span electrical, furniture, toys and food and drink, was marked up 8¼p to 283p as Goldman Sachs and Jefferies both started coverage with a buy rating. B&M floated last month at 270p giving it a market value of about £2.8billion.

Goldman said B&M could grow to 850 stores as it expands its presence in the South.

The broker added: “We believe the company’s format has the potential to be highly disruptive within the UK retail landscape. It follows many of the retailing principles of the German companies Aldi and Lidl but with a targeted, branded grocery and general merchandise offer.”

Jefferies was more cautious on the outlook for Poundland, 4¼p easier at 321p, while another stock market newcomer, Pets at Home, drifted 3½p lower to 183p.

Gas and energy supplier SSE and London Stock Exchange, down 43p to 1498p and 26p to 1920p, were among the big blue chip fallers as their shares traded without the right to the latest dividend.

Engineer Weir Group fell 44p to 2704p amid speculation it could go on the acquisition trail.

Finnish mining technology company Outotec has been touted as a possible target but denied it had been approached.

We believe the company’s format has the potential to be highly disruptive within the UK retail landscape

Goldman Sachs

A bullish production update lifted mining heavyweight BHP Billiton 12p to 2066½p, while copper producer Kazakhmys struck it 26p richer to 344¾p as it set out plans to split up the company.

Catalytic converters group Johnson Matthey misfired 37p to 3022p as it signalled a bigger-than-expected hit from the strong pound.

Software giant Sage Group dipped 4p to 377p as dealers noted weakness in its North American payments business in its trading update.

The FTSE 100 Index closed 2.81 points ahead at 6798.15.

Electricals chain Dixons Retail and mobile phones retailer Carphone Warehouse sparked 1½p and 10½p higher to 51¼p and 333p as they close in on their merger.

On Wall Street, the Dow Jones was down 26.91points to 17,086.63 by close.